This program for Training in Radiation Oncology Sciences (TROS) is to provide opportunities of laboratory and/or clinical research to clinicians and scientists. The overall objective is to promote the development of full-time academic careers targeted to integrating clinical, biological and physical investigation in radiation oncology, so as to improve the management of cancer. Radiotherapy is a multidisciplinary practice involving radiobiology, medical physics and clinical oncology. Increase in our radiobiological knowledge may further enhance the scientific basis and improve treatment approaches of radiotherapy. The application of advanced physics, computer and engineering technology may also impact on the success of radiotherapy. Optimum integration of these scientific and technical fields into clinical practice requires personnel that are cross-trained in the multiple facets that constitute radiation oncology. A major goal of this program is to contribute to such integration. The participating faculty has career paths that integrate laboratory and clinical research. Thus, they could serve as role models for the potential trainees. In addition, our team is comprehensive and integrated in terms of meshing together the expertise in biology, physics and clinical radiotherapy. One example for such integration is the research of intensity modulated radiotherapy (IMRT), involve computer aided optimization, biophysical modeling and radiobiological investigation, and clinical study. Our research program has three special emphases. The first is in IMRT that involves significant technological advancement, requiring integration of physics, engineering and clinical medicine. The second, in molecular radiobiology, is motivated by the rapid increase in our knowledge of tumor genotype and phenotype with molecular biology approaches. The third is in biological and molecular imaging, which combines our understanding of the molecular basis of cancer and advanced imaging. The mentors of TROS have developed major research programs in these areas. An important goal of this program is to provide resources for training clinicians and scientists in these directions of radiation oncology research and to build the necessary interface between the laboratory and the clinic in the era of molecular medicine.